Feedback of channel quality information

Abstract

Methods and apparatus are presented for improving the feedback of channel information to a serving base station, which allows a reduction in the reverse link load while allowing the base station to improve the forward link data throughput. Over a channel quality indicator channel, a carrier-to-interference (C/I) symbol is transmitted over multiple slots at a reduced rate, which increases the likelihood that the base station can decode said symbol. The reduced rate mode can be selectively triggered by a high velocity condition or other unfavorable channel condition. The C/I symbol is used to determine transmission formats, power levels, and data rates of forward link transmissions.

1. A base station for controlling the operation of a quality feedback channel in a wireless communication system, comprising:
 a scheduler for interpreting a channel quality value associated with a transmission channel 
 and for determining a condition of the transmission channel; and 
 a base station transmission subsystem for transmitting a message to a remote station transmission subsystem to transmit the channel quality value having a fixed quantity of bits over one slot of the channel quality feedback channel if the transmission channel condition is favorable, and 
 to transmit the channel quality value having the fixed quantity of bits over a plurality of slots of the channel quality feedback channel if the channel condition is not favorable. 
 
     
     
       2. The base station of  claim 1 , wherein the condition of the transmission channel is based upon a velocity estimate. 
     
     
       3. The base station of  claim 1 , wherein the condition of the transmission channel is based upon a power level estimate. 
     
     
       4. The base station of  claim 1 , wherein the condition of the transmission channel is based upon whether a fast fade occurs in the transmission channel. 
     
     
       5. A remote station for improving the reception of a channel quality value, comprising:
 a receiving subsystem for determining whether the condition of a transmission channel is favorable; and 
 a transmission subsystem for transmitting the channel quality value having a fixed quantity of bits over one slot of a feedback channel if the condition of the transmission channel is favorable, and 
 for transmitting the channel quality value having the fixed quantity of bits over more than one slot of the feedback channel if the condition of the transmission channel is unfavorable. 
 
     
     
       6. The remote station of  claim 5 , wherein
 the transmission subsystem repeats the channel quality value over a frame of the feedback channel if the channel quality value is transmitted over more than one slot. 
 
     
     
       7. The remote station of  claim 5 , wherein the channel condition is unfavorable if the remote station and a station travel at a high velocity in relation to each other, wherein the remote station originates the feedback channel and the station originates the transmission channel. 
     
     
       8. A method for improving the reception of a channel quality value at a base station, comprising:
 determining whether the condition of a feedback channel from a remote station is favorable; 
 if the condition of the channel is unfavorable, then transmitting a control signal to the remote station, wherein the control signal triggers a reduced rate mode for transmitting the channel quality value having a fixed quantity of bits over a feedback channel from the remote station; and 
 if the condition of the channel is favorable, then allowing the remote station to control the transmission of the channel quality value having the fixed quantity of bits over the feedback channel. 
 
     
     
       9. An apparatus for improving the reception of a channel quality value at a base station, comprising:
 means for determining whether the condition of a feedback channel from a remote station is favorable; 
 means for transmitting a control signal to the remote station if the condition of the channel is unfavorable, wherein the control signal triggers a reduced rate mode for transmitting the channel quality value having a fixed quantity of bits over a feedback channel from the remote station; and 
 if the condition of the channel is favorable, then allowing the remote station to control the transmission of the channel quality value having the fixed quantity of bits over the feedback channel.